Apparatus for pumping volatile liquids



Aug. 11, 1942.

O. A. HANSEN APAfiATus FOR PUMPING A VOLATILE LIQUID Filed June 15, 1 940 w a. 1.7. awawfi 022 .7 Wain? TTORNEYS I Patented Aug. 11, 1942 UNITED STATES PATENT OFFICE APPARATUS rc r t lgigiNe VOLATILE Odd A. Hansen, Kenmore, N. Y., assignor to The Linde Air Products Company, New York, N. Y., a corporation of Ohio Application June 15, 1940, Serial No. 340,849

' Claims. (Cl. 103-153) This invention relates to apparatus for pumping volatile liquids and particularly to plunger pumps adapted for pumping liquefied gases which have boiling point temperatures materially below 273-K. at atmospheric pressure, suchas liquid oxygen, against relatively high heads of pressure, for example, against a head of pressure of from I 1000 to 2000 lbs. per square inch gauge.

The invention has for its object generally the provision of an improved construction and arrangement of parts for pumps of the character indicated which achieves precision of movement of the working parts and also assists in excluding heat from the liquid being pumped andin the lubrication of the pump plunger.

More specifically, the invention has for its object the provision of an improved construction for the pump cylinder of a plunger pump adapted for pumping highly volatile liquefied gases, such as liquid oxygen, in which liquid displacement from the pump chamber is accomplished by the guiding the same and is of a character which ex- 25 cludes heat and is also self-lubricating.

as a packing sleeve. The-sleeve element. I2 is preferably mounted at its top in a plate element l3 that may be a component of frame or casing that affords rigid support to the pump-assembly (the showing of such frame or casing bein omitted from the drawing in the interests of clearness of illustration). The elements l0, II and I2, while they may be integral, are preferably, separable, the attachment to one another being achieved in any convenient manner, for example, by threaded joints, as shown.

The cylinder assembly is completed by means of a block-like element l4- that is shown as threadedly attached to the lower end of the cyl-- inder Ill. The block l4 thus closes, the lower end of the pump chamber and forms a suitable head for the cylinder, in which a plunger [5 is reciprocated.

The block I4 is preferably counterbored, as shown at It, to provide a liquid receiving space, and has a supply connection I! that communis cates with the receiving space 16 through a Another object of the invention is to provide a guiding bushing of atype which is suitable also for operation at relatively low temperatures and in the presence of a chemically active liquid agent, such as'liquid oxygen, when at a relatively high pressure.

Other objects'of the inventionwill in part be obvious and will in part appear hereinafter.

The invention accordingly comprises the features of construction, combination of elements, and arrangement of parts, which will be exemplifled in the construction hereinafter set forth, and the scope of the invention will be indicated in the claims.

For afuller understanding of the nature and objects of the invention reference should be had to the following detailed description taken in connection with the accompanying. drawing, in which:

The figure is a view, mainly in section, showing a plunger pump for pumping liquid oxygen, arranged in accordance with the invention.

Referring now to the drawing, a vertically arranged cylinder assembly is shown comprising a cylindrical element Ill formed with a pump cham- -ber to receive liquid and having amelatively thick wall.-'The cylinder vIll is attached at the upper end to a second element ll arranged to close one end. of the pump chamber, and has a third elechannel l8; the latter being bored in the block I and formed with an offset portion having a valve seat on which a valve element l9 seats. The

valve element is arranged to open in response to the incoming stream of liquid 'and' is therefore biased to closed position. Any convenient arrangement for this purpose may be employed, for example, a gravity seating arrangement, as shown. Access to the valve chamber in the block I4 is provided in any convenient manner, for example, by means of ,a removable. plug I 9'. The extent 'to which the block I4 is counterboredat I6 is merely such as to provide a space beneath the plunger suflicient to receive and collect any solid-bodies in the incoming liquid. The lower end of the pump casing is accordingly provided with a blow-ofl outlet which is shown closed by a removable plug l6.

In'order that liquid may be displaced from the pump chamber by the countermovement of liquid and plunger, a. clearance space in the cylinder III at the sides of the plunger is also provided,

whereby-liquid may flow upwardly when the plunger moves downwardly. This latterclearance space is shownat 20 and leads to an offset outlet connection 2 I, which communicates at the upper end with the clearance space 20 through a lateral bore in the element ll.

the passage in the valve housing at a point he- Connection 2|. leads to and communicates with anothei valve yond the valve seat. chamber is provided 28'.

In order to provide the pump with a bushing, in accordance with the invention, adapted both to guide and to lubricate the plunger l5 and which also excludes heat, the element II is counter-1 bored interiorly to a point considerably beyond the threads which engage an end of the element l0, andinto this counterbored portion is fitted a bushing 25 of an inert material which both excludes heat and is self-lubricating. The material at present preferred for this purpose is a bonded graphite. The clearance of the bushing about the plunger is made relatively small andpreferably not over .001 inch for plungers of the order. of one inch in diameter. Axially the bushing is preferably given a length approximately equal to or greater than the stroke of the plunger. This will prevent any portion of the plunger, which has been heated by packing friction, from entering the liquid chamber.

The lower end of the graphite bushing is seen to be flush with the upper endof the enlarged portion of the deep cylindrical recess in block I I, the recess being preferably shaped or counterbored to receive a spacing collar 26 which is of metal, clears the plunger, and adapted to hold the bushing in'place against any tendency to Access to the outlet valve through the removable plug downward displacement. The diameter of the counterbored recess is slightly greater than that employed for the bushing 25; the collar 26 located in the recess being also preferablybored through radially at a point communicating with the connection 2| in order to afford a suitable exit for the liquid displaced from the pump chamber. Between the collar 26 and the cylinder ID, a sealing washer 26' is also preferably inserted to insure a pressure-tight joint between cylinder l0 and block ll.

The sleeve l2, at its lower end, has a gland l2 adapted to engage the threaded nipple of element ll, while the upper end of the sleeve is closed by a gland or follower 21 that preferably has an exterior shoulder or collar adapted to be engaged by a' nut 28, which is arranged to be in screw-threaded engagement with the exterior of the sleeve. The gland or follower is arranged to press down upon a plurality of packing rings 29, which are shown as filling the space in the packing sleeve between its inner wall and the plunger l5. These packingrings are preferably of a special construction and when liquid oxygen is being pumped are of a composition avoiding the use of a hydrocarbon or other'substance that may react with the liquid oxygen. A preferred form of packing ring forsuch service comprises a washer-like body of suitable inert compressed material, such as shredded asbestos, incorporating an inert solid lubricant in comminuted form,

for example, flake graphite, as disclosed in co- 'ployed, together with the of plunger IS. The plunger, when moved upwardly, executes the suction stroke; the plunger moving from the lowermost position to the uppermost position to execute a complete stroke. The discharge stroke then follows; the plunger moving in the opposite direction or from-uppermost position to lowermost position.

The relatively long packing sleeve here emrelatively large amount of packing, is, of course, flttedtightly into the space in the gland about the plunger ii, in order thereby to avoid leakage and to prevent the escape of any substantial quantity of or shown in the accompanying drawing shall be I pending application, Serial No. 341,126, filed June 18, 1940, in the name of J. F. Patterson.

The plunger 15 is provided at its upper end i with a transverse opening 30, or other suitable means, by which it may be mechanically coupled to suitable driving means,- for example, by a pin to a walking beam (omitted from the drawing in the interests of clearness of illustration).

In operation, the liquid oxygen, or other highly volatile fluid that is to be pumped, is introduced to the pump chamber through the inlet connection t1, the valve l9 being opened by the impact of the fluid which passes into the cylinder chamber, under the influence of the suction stroke the volatile material being pumped. This engagement of the packing with the plunger necessarily generates heat in the plunger l5, mainly in its surface, when the pump is working. Some of the heat thus generated is conductively transmitted to the block H. The transference of this heat to the liquid being pumped while in the upper part of the pump chamber, where it would impede pumping, is in large measure blocked by the bushing 25 which is interposed between the packing and the pump chamber. The reduced clearance provided, as indicated above, insures that the bushing shall also serve as a self-lubricating guide for the plunger.

The method and arrangement of connections for operating the pump above described are disclosed and claimed in copending application, Serial No. 340,848, filed June 15, 1940 in the name of O. A. Hansen.

Since certain changes may be made in the above construction and different embodiments of the invention could be made without departing from the scope thereof, it is intended that all matter contained in the above description interpreted as illustrative and not in a limiting sense.

Having described my invention, what I claim as new and desire to secure by Letters Patent is;

1. In apparatus for pumping a volatile liquid having a boiling point temperature materially below 273 K. at atmospheric pressure, the combination with a low pressure supply of such liquid, of a pump assembly comprising a cylinder formed with a pump chamber and having a closure at the suction end provided with a valve controlled inlet passage communicating with said supply, a single-acting plunger arranged to reciprocate in said cylinder and to clear the in- .ner wall thereof providing thereby an appreciable clearance space, a discharge passage provided with a valve and communicating withsaid clearance space, a gland element closing said cylinder and afl'ording entrance for said plunger and provided with a packing space, an inert lubricated packing for said plunger in said packing space, and a solid self-lubricating and relatively closefitting bushing for said plunger of a length at least as long as the stroke of said plunger and disposed in said assembly between said packing space and said clearance space.

2. In apparatus for pumping a volatile liquid having a boiling point temperature materially below 273 K. at atmospheric pressure, the combination with a low pressure supply of such liquid, of a pump assembly comprising a vertically mounted cylinder recessed to provide a pump chamber, a head closing said cylinder at its lower end and provided with an inlet passage adapted clear the inner wallthereof "providing thereby an appreciable clearance space, a closure for the upper end of said cylinder provided with an outlet passage communicating with said clearance space,

v a flow actuated valve controlling said outlet, a

closely about said plunger, said bushing having an axial length sufficient to impede adequately the transfer of heat from said packing to said pump chamber.

3. In apparatus for pumping a volatile liquid having a boiling point temperature materially bc- I low 273 K. at atmospheric pressure, the com-- bination with a low pressure supply of such liq uid, of a pump assembly comprising a vertically mounted cylinder recessed to provide a pump chamber, a head closing said cylinder at itslower end and provided with an inlet passage adapted to be connected to said supply, flow actuated valve controlling said inlet, said valve being located on the-exterior of said cylinder and provided with means affording access thereto, a single-acting plunger arranged to reciprocate in said cylinder and to clearthe inner wall thereof providing thereby an appreciable clearance space, a closure for the upper end of said cylinder provided with an outlet passage communicating with said clearance space, a flow actuated valve controlling said outlet, said second-named valve being located on the exterior of said cylinder and provided with means affording access thereto, a gland element associated with said last-named closure in which said plunger works and provided with a space adapted to receive annular packing for sealing the passage of said plunger, and a bushing of solid self-lubricating material of alengthat least equal to the stroke of said plunger and disposed in said last-named closure about said plunger for effectually impeding transfer of heat from said packing to said pump chamber.

4. In apparatus for pumping liquid oxygen,

' the combination with a'low pressure supply of such liquid, of a pump assembly comprising a vertically' mounted cylinder recessed to provide a.

pump chamben-a head closing said cylinder at its. lower end and provided with an inlet passage adapted to be connected to said supply, a gravity controlled valve controlling said inlet, a singleacting plunger arranged to reciprocate in said cylinder and to clear the inner wall thereof providing thereby an appreciable clearance space. a closure for the upper end of said cylinder provided with an outlet passage communicating with said clearance space, a flow and gravity actuated valve controlling said outlet, a gland element associated with said last-named closure in which said plunger works and provided with aspace adapted to receive annular packing for sealing the passage of said plunger, and a bushing of bonded graphite having a length at least equal to that of a plunger stroke and disposed in said last-named closure about said plunger for effectuall impeding transfer of heat from said packing to said pump chamber.

5. ml apparatus for pumping a volatile liquid having a boiling point temperature materially below -.2'73 K. at atmospheric pressure, the com.- bi'nation-with a low pressure supply of such liqdid, of a pump assembly comprising a vertically m'ounted cylinder recessed to provide a pump chamber, a head closing said cylinder at its lower end and provided with an inlet passage adapted to be connected to said supply, a valve controlling said inlet, a single-acting plunger ar-' ranged to reciprocate in said cylinder, an outlet for said cylinder, a closure for'the upper end of said cylinder, a valve controlling said outlet, a gland element associated with said last-named closure in which said plunger works and provided with a space adapted to receive annular packing for sealing the passage of said plunger, and

bination with a source of supply of such liquid,

of 'a pump assembly comprising a cylinder formed with a pump chamber, a connection thereto from said 7 source of supply, valve means controlling said connection, a pump plunger arranged to reciprocate in said cylinder and having an appreciable clearance with respect to the walls of the pump chamber, a discharge passage communicating with a high point of said chamber, valve means therefor, a gland and packing meam through which said plunger operates at one end of the pump assembly, and a close-fitting guide bushing for said plunger'located interiorly ofthe pump with respect to said gland and packing.

means, said bushing being of solid self-lubricating material and having a substantial axial length suflicient to impede adequately transfer of heat from said packing to said pump chamber.

'7. In apparatus for pumping a volatile liquid having'a boiling point temperature materially below 273 K. at atmospheric pressure, the combination with a source of supply of such liquid of a pump assembly comprising a cylinder formed with a pump chamber, a connection thereto from said source of supply, valve means controlling said connection, a pump plunger arranged to reciprocate in said cylinder, a discharge passage with valve means therefor, a gland and packing means through which said plunger operates at one end of the pump assembly, and a close fitting guide bushing for said plunger of a length substantially equal at least to the stroke of the spect to said gland and packing means, said bushing being of inert solid self-lubricating material whereby the heat transferred to the liquid in the pump chamber from that generated by friction at said packing means is restricted at least toan immaterial amount.

8. In apparatus for pumping a volatile liquid having a boiling point temperature materially below 273 K. at atmospheric pressure, the combination with a source of supply of such liquid, of a pump assembly having a pump chamber, a plunger adapted to reciprocate therein, a valve controlled inlet connection from said sourceto said cylinder. a valve controlled discharge passage.- packing means for sealing the chamber about the opening for said plunger, and a guide bushing for-said plunger ldcated irrteriorly er thepump with respect to said packing means,

- said guide bushing being of solid self-lubricating length and close .fitting about said plunger, whereby the heat transferred to the liquid in the pump from that generated by friction at said packing means is restricted at least to a low value.

9. In apparatus for pumping a volatile liquid having a boiling point temperature materially below 273 K. at atmospheric pressure, the combination with a source of supply ofsuch liquid, of a pump assembly comprising a cylinder formed with a pump chamber and provided with a valve controlled inlet passage communicating with said supply, a pump plunger arranged to reciprocate in said cylnder and to clear the inner wall of the pump chamber providing thereby a clearance space, a discharge passage provided with a valve and communicating with a high point of said clearance space, a gland and packing means through which said plunger operates at one end of the pump cylinder, and a solid self-lubricating guide bushing of substantial length fitted around said plunger and disposed in said assembly between said packing means and said clearance space, said discharge passage communicating with said clearance space at a point thereof adjacent said bushing.

10. In apparatus for pumping a volatile liquid having aboiling point temperature materially below 273 K. at atmospheric pressure, the combination with a low pressure supply of such liquid 0! a pumpassembly comprising a cylinder formed with a pump chamber and provided with a valve controlled inlet passage communicating with said supply, a pump plunger arranged to reciprocate in said cylnderand to clear the inner walloi the pump chamber providing thereby a clearance space, a discharge passage provided with a valve and communicating with a high point oi said clearance space, a gland and packing means through which said plunger operates at one end of said cylinder, and a close fitting solid self-lubricating bushing for said plunger of a length about as long as the stroke of said plunger and disposed in said cylinder between said packing means and said clearance space, whereby the heat transferred to the liquid in the pump chamber from that generated by' friction at said packing means is restricted at least to an immaterial amount.

ODD A. HANSEN. 

